New research shows people have more sex in countries with greater gender equality. Some think this is because women put a high "price" on sex — but there may be other explanations.

According to USA Today, a study of 37 countries "found that countries ranked higher in gender equality also generally had more casual sex, more sex partners per capita, younger ages for first sex and greater tolerance/approval of premarital sex." The reason, says study author Roy Baumeister, has to do with women's sexual and economic calculations: "If women don't have many opportunities to make money on their own, they need the value of sex to be as high as possible. When women don't have other opportunities, sex is the main thing she has to offer." According to Baumeister, women will hold out longer for sex if they can't get power in other ways: "In countries where women are at a big disadvantage, they restrain sex, so the price is high and men make a lifetime commitment to support them to get sex. Men will do whatever is required for sex."

This may be true, especially insofar as women with few economic opportunities need to secure support from men. But there are several other explanations for the findings. The data on sexual behavior were presumably self-reported, meaning what Baumeister really studied was how much casual and/or premarital sex people said they had. And countries with poor gender equality also often have strong prohibitions against women having premarital sex — in fact, constraints on women's sexual behavior are one of the hallmarks of inequality. So women in such countries might well under-report their number of partners, driving the total number of "partners per capita" down. Also, women (and men) in these countries may have less casual sex because it's socially stigmatized, not because women are "restraining sex."

Baumeister may have controlled for these factors somehow — I've requested a copy of the study, but haven't received one as of this writing. However, the USA Today makes no mention of them. And thus we have a picture of women making decisions about their economic and sexual status and men blithely following along. The truth, unfortunately for women, may be far more complicated.